<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>插值</title>
</head>
<body>


<div id="app">
    <!--
    mustache
    胡须表达式
    单向数据流    -->
    {{ message }}
    {{ 1==1 }}
    {{message.concat('t')}}


<!--双向数据流    -->
    <input type="text" v-model="username">{{username}}

</div>
</body>
<script src="https://unpkg.com/vue@3/dist/vue.global.js"></script>
<script>

    var app = Vue.createApp({
        data: function () {
            return {
                message: 'hello',
                username:'username'
            }
        }
    });

    app.mount('#app');


</script>

</html>